649239840 has 96 divisors (see below), whose sum is σ = 2272354560. Its totient is φ = 173129472.

The previous prime is 649239803. The next prime is 649239847. The reversal of 649239840 is 48932946.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (649239847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70824 + ... + 79463.

It is an arithmetic number, because the mean of its divisors is an integer number (23670360).

Almost surely, 2^649239840 is an apocalyptic number.

649239840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

649239840 is an abundant number, since it is smaller than the sum of its proper divisors (1623114720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

649239840 is a wasteful number, since it uses less digits than its factorization.

649239840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150311 (or 150297 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 649239840 is about 25480.1852426547. The cubic root of 649239840 is about 865.9012914036.

The spelling of 649239840 in words is "six hundred forty-nine million, two hundred thirty-nine thousand, eight hundred forty".